Online PHP editor | output for V4sUS

<?php $first = [ 3 => [['id' => 1, 'number' => 0, 'time' => 40,]], 4 => [['id' => 2, 'number' => 0, 'time' => 40,]], 5 => [['id' => 3, 'number' => 0, 'time' => 40,]], 6 => [['id' => 1, 'number' => 0, 'time' => 41,]], 7 => [['id' => 2, 'number' => 0, 'time' => 41,]], 8 => [['id' => 3, 'number' => 0, 'time' => 41,]], ]; $second = [ 3 => ['id' => '1', 'number' => '3785', 'time' => '40'], 4 => ['id' => '2', 'number' => '1574', 'time' => '40'], 5 => ['id' => '1', 'number' => '2954', 'time' => '41'], 6 => ['id' => '2', 'number' => '2463', 'time' => '41'], ]; $map = []; foreach ($first as $k => [['id' => $id, 'time' => $time]]) { $map["{$id}_{$time}"] = $k; } foreach ($second as $row) { $key = $map["{$row['id']}_{$row['time']}"]; $first[$key] = $row; } var_export($first);